What would I need to build to power/use speakers for a 7.1 home theater setup?

A friend just gave me speakers from his 7.1 home theater setup. His kids fried the receiver and I don't have one. I'm wondering how hard it would be to put together a simple setup to use them as a 7.1 system again? I don't need dolby or thx or any of that other decoder stuff. I just need to be able to hook them up to an HTPC. Some kind of amp/driver and the ability to change the volume is what I am looking for. Any ideas?

The speaker satellites are all 40w 4ohms with the bass being double at 80w 8ohm. So long as I get a 40w amp kit that'll work for the satellites and an 80w for the bass? And dual mono or stereo kits? I'm guessing stereo since that's probably how the PC will handle the audio.